The Fourth Gordon Conference on Molecular Mechanisms of Microbial Adhesion will be held June 27- July 3, 1993 at Salve Regina College in Newport, Rhode Island. The Conference will consider the latest scientific developments in elucidating the structural attributes of microbial adhesins and the regulation of their synthesis, the nature and modulation of receptors that interact with adhesins and whose expression and function are often influenced by chemical signals elicited by the microorganism, and the forces that facilitate and govern the interaction between adhesins and receptors. In the past, there has been considerable emphasis at this Gordon Conference on microbial cell surface structures serving as adhesins or necessary for adhesion. These included consideration of lipoteichoic acid, teichoic acids, peptidoglycan, capsular molecules, lipopolysaccharides, pili or fimbriae, flagella and an array of surface proteins. Although these surface adhesins will undoubtedly be mentioned on numerous occasions, the focus of the Conference will be more on the nature of the interactions between these adhesins and receptors to permit microbial attachment. One session will be devoted, however, to the characterization of less well understood cell surface structures as putative adhesins. Much of the conference will be devoted to elucidating the interactions between bacteria and mammalian host tissues that precede appearance of symptoms and disease. An overriding concern will be the molecular basis for the specificity between the adhesins and receptors and the characterization of the forces that permit stable interaction. From the point of view of the microorganism, we will consider how synthesis and placement of adhesins are regulated, how the microbe sends out signals that cause the target cell to display receptors and to actively take part in the adhesive interaction which in some cases is followed by invasion of the microbe into the eukaryotic cell. The overall plan for the conference is to seek the involvement of the world's experts on all facets of microbial adhesion so that a truly challenging and interdisciplinary meeting can be held. In the belief that those working on microbial adhesion can benefit from discoveries of others, we will include several speakers with considerable expertise on the detailed interactions between eukaryotic cells and components of the extracellular matrix. We will also consider details of the adhesive and aggregating interactions between microorganisms leading to gene transfer and to the molecular signaling of events that occur in plant-microbe interactions leading to nitrogen fixation by Rhizobium species on leguminous plants. Foreign scientists have made significant contributions to the science that is the subject of this conference, Funds are requested for travel of some of these scientists. We are also proposing to provide financial support for some 20 graduate students and postdoctoral investigators, to partially defray expenses of their attendance and participation which we deem to be highly desirable. Based on the interest and importance of the topics to be presented and discussed, we anticipate that this will be an important and oversubscribed Gordon Conference.